/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
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 * 1. Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
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 * 3. Neither the name of the copyright holder nor the names of its contributors 
 * may be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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package org.hisp.dhis.period;

import com.google.common.collect.Lists;
import java.time.LocalDate;
import java.time.temporal.WeekFields;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.hisp.dhis.calendar.Calendar;
import org.hisp.dhis.calendar.DateInterval;
import org.hisp.dhis.calendar.DateIntervalType;
import org.hisp.dhis.calendar.DateTimeUnit;

/**
 * @author Morten Olav Hansen <mortenoh@gmail.com>
 */
public abstract class WeeklyAbstractPeriodType extends CalendarPeriodType {
  protected final String name;

  protected final int startOfWeek;

  protected final String isoFormat;

  protected final String isoDuration;

  protected final int frequencyOrder;

  protected final String sqlInterval;

  protected final String weekPrefix;

  protected WeeklyAbstractPeriodType(
      String name,
      int startOfWeek,
      String isoFormat,
      String isoDuration,
      int frequencyOrder,
      String sqlInterval,
      String weekPrefix) {
    this.name = name;
    this.startOfWeek = startOfWeek;
    this.isoFormat = isoFormat;
    this.isoDuration = isoDuration;
    this.frequencyOrder = frequencyOrder;
    this.sqlInterval = sqlInterval;
    this.weekPrefix = weekPrefix;
  }

  public int getStartOfWeek() {
    return startOfWeek;
  }

  @Override
  public String getIso8601Duration() {
    return isoDuration;
  }

  @Override
  public int getFrequencyOrder() {
    return frequencyOrder;
  }

  @Override
  public String getSqlInterval() {
    return sqlInterval;
  }

  @Override
  public String getIsoFormat() {
    return isoFormat;
  }

  @Override
  public Period createPeriod(DateTimeUnit dateTimeUnit, Calendar calendar) {
    DateTimeUnit start = adjustToStartOfWeek(new DateTimeUnit(dateTimeUnit), calendar);
    DateTimeUnit end = new DateTimeUnit(start);
    end = calendar.plusDays(end, calendar.daysInWeek() - 1);

    return toIsoPeriod(start, end, calendar);
  }

  @Override
  public DateTimeUnit getDateWithOffset(DateTimeUnit dateTimeUnit, int offset, Calendar calendar) {
    return calendar.plusWeeks(dateTimeUnit, offset);
  }

  /** Generates weekly Periods for the whole year in which the given Period's startDate exists. */
  @Override
  public List<Period> generatePeriods(DateTimeUnit start) {
    Calendar calendar = getCalendar();
    List<Period> periods = new ArrayList<>();
    start = new DateTimeUnit(start); // create clone so we don't modify
    // the original start DT

    start.setMonth(1);
    start.setDay(4);
    start = adjustToStartOfWeek(start, calendar);

    for (int i = 0; i < calendar.weeksInYear(start.getYear()); i++) {
      DateInterval interval = calendar.toInterval(start, DateIntervalType.ISO8601_WEEK);
      periods.add(new Period(this, interval.getFrom().toJdkDate(), interval.getTo().toJdkDate()));

      start = calendar.plusWeeks(start, 1);
    }

    return periods;
  }

  /** Generates the last 52 weeks where the last one is the week which the given date is inside. */
  @Override
  public List<Period> generateRollingPeriods(DateTimeUnit end, Calendar calendar) {
    List<Period> periods = Lists.newArrayList();
    DateTimeUnit iterationDateTimeUnit = adjustToStartOfWeek(end, calendar);
    iterationDateTimeUnit = calendar.minusDays(iterationDateTimeUnit, 357);

    for (int i = 0; i < 52; i++) {
      periods.add(createPeriod(iterationDateTimeUnit, calendar));
      iterationDateTimeUnit = calendar.plusWeeks(iterationDateTimeUnit, 1);
    }

    return periods;
  }

  @Override
  public String getIsoDate(DateTimeUnit dateTimeUnit, Calendar calendar) {
    int year;
    int week;

    if (calendar.isIso8601()) {
      LocalDate date =
          LocalDate.of(dateTimeUnit.getYear(), dateTimeUnit.getMonth(), dateTimeUnit.getDay());
      WeekFields weekFields = WeekFields.of(PeriodType.MAP_WEEK_TYPE.get(getName()), 4);

      year = date.get(weekFields.weekBasedYear());
      week = date.get(weekFields.weekOfWeekBasedYear());
    } else {
      dateTimeUnit = adjustToStartOfWeek(dateTimeUnit, calendar);
      week = calendar.week(dateTimeUnit);

      if (week == 1 && dateTimeUnit.getMonth() == calendar.monthsInYear()) {
        dateTimeUnit.setYear(dateTimeUnit.getYear() + 1);
      }

      year = dateTimeUnit.getYear();
    }

    return String.format("%d%s%d", year, weekPrefix, week);
  }

  @Override
  public Date getRewindedDate(Date date, Integer rewindedPeriods) {
    Calendar cal = getCalendar();

    date = date != null ? date : new Date();
    rewindedPeriods = rewindedPeriods != null ? rewindedPeriods : 1;

    DateTimeUnit dateTimeUnit = createLocalDateUnitInstance(date);
    dateTimeUnit = cal.minusWeeks(dateTimeUnit, rewindedPeriods);

    return cal.toIso(dateTimeUnit).toJdkDate();
  }

  public DateTimeUnit adjustToStartOfWeek(DateTimeUnit dateTimeUnit, Calendar calendar) {
    int weekday = calendar.weekday(dateTimeUnit);

    if (weekday > startOfWeek) {
      dateTimeUnit = calendar.minusDays(dateTimeUnit, weekday - startOfWeek);
    } else if (weekday < startOfWeek) {
      dateTimeUnit = calendar.minusDays(dateTimeUnit, weekday + (frequencyOrder - startOfWeek));
    }

    return dateTimeUnit;
  }
}
